Document 8R9abdNrD6R3xgGEDZD07vxve

f: r- t' ;; Sic. r i July , 1*7J SCBJtCf I AERRIWT on LEAD HOISE BARRIERS TO THE KEWEKS OT THE LEES XNDOSTItXEl ASSOCIATION, IC. I Attached la a reprint of aa artlcla prepared and placed by our publicity agency In ELECTRICAL WORLD Magasine. The article tell* bow a Major utility uaed aheet lead in prefabricated panels to solve a community noise problem. ELECTRICAL w o r l d is considered a key *utilities* publication and has a twice-Monthly circulation of 34,500. Xany cities and other governmental entities, being faced with high industrial noise levels, are drafting legislation designed to limit excessive sound beyond a plant's property lines. These regulations would supplement the already existing OSHA regulations on in-plant noise. Such new controls may have a positive effect on the demand for noise barrier materials, one of the most efficient of which is lead. Should you have questions on this subject, or require additional copies of the attached reprint, please contact us. Sincerely# JTSilm Attachment r.vjerome Smith Secretery t Generel Manager ;* I i I sr f s If r k . i f I % S. May 15,1973 --J S N 3500.01 Bedroom community's quiet undisturbed 1 A* a resell of m anlinoiie-orteetcO conrtrwctioa project now Marini complauon, (lie Long ItUid ti|Min| Co (Likx>) pp* plant *t Nocthpurt, N.Y., remains one o( (he utility industry's qui etest rmul-fucl genefsitog ttibotu. The problem uko faced n. "Hoe Id increase the capacity of a lafte fence* Mu| station is the middle of s *bedrexxs' restdeeUal cominanity without generating huge noise problem!?*4 Lko'i solution uvoired the cjUeawve me of acooitK bamm. plus *<**edamprwrd taUke ducts- both retying os the ftoi>e-deadening chacectcratscs of ahect Wad. There arc three tOO-M generating sum at the Noethport plant The recent aattmua prograa involved the msSallauan of new equipment a* folk**: Induced-draft-fa* equipment and aasnciitcd ductwork. which are being --tailed to MDfron the operating cAono of Una l, installed in 196?. and Luc 1 suaalWd is l96*. n Induced-draft-fan equipment and aaxuud ductwork and an eWctrcnUtic preopvtaioe. which are bemg installed m oripaal cqupment for Unit 3, vh*ch neat on line n 1*72. To undcnUAd the problems Liioo faced is soundproofing the new equip ment. u necessary to understand why the utility h so concerned with soar centred at its Northport plane Situated on Long Island Sound, (hr plant n Banked on three ode* by a quiet suburban reudettui community. It con tains more thaa TOO homes, tome of which are as chwe as 1.200 ft to (he ymxr-nation structures. Eacept foe (hr rkx> plant Northport has no commeroal or business tones, oe even ary nearby commensal oe industrial devel opments The ares site is removed from ruouvt vehicular, sir. or rail traffic. feecauvc of the ki ambient deabc! loch a the community. Like engi neers faced particularly difficult no**ecvwtrol problem uhea the first two units uerc being designed They knew that oprrU>a of the machinery and s mo o * atrd equipment for the two units would produce sourcc-sourd* ta the 90-U>-l30db range, and that such lcveb would anan homeowners ia the surrounding nunmunity. Further complicating the |wvblem was the fact that such sound would travel far ia the quiet suburban atmosphere. Studies ia 1963 of community sound Wvets determined that s 3-to-3 drcibrl increase in ambient sound Icvd would be acceptable, and would avoid wide spread complaints from homsownm. Therefore, when the plant was being designed. Dlao specified that none from the plant could not eaceed ?0 db outside (he general plant walls, and 90 db immediately outside the eahaust ductwork and wall* of the mechanical particulate collectors of each unit To accomplish these goals, four basic nepa were involved: Vshout equipment inside (he plant was purchased with low sound level where practicable, or were enclosed in sound-deadening materials. n Wherever needed, walls and ced ing! inside the plant were covered with towad-absortwng panels and materials. u The enure plant was tsdoul in sownd-deademng walk an' Acoustic silencers were provided for forced-draft fans and ventilating systems. As a result, when Units I and 2 were initially completed Like had no need to be concerned with aocse complaints from the community. When the recent a made to duced-draA-faa equipment in Unit |, however, additional noise-reduction work was required, fecesuse the IO fans and their associated ductwork art too Urge to be Installed inside the plane the cutting plant walls could not be weed even partially to attenuate sound. So al ternative notsc-eedwction methods had to be implemented. Tests conducted within (he duerwotk on the exhaust side of the iadwccd-driA fan installed in Unit I revealed an aver age reading of 125 db. a sound level far ta eacca cf the original 90-db level set for nosse outside the plant wall. As an indication of what the 125-db sound level means, h can be compared to (he sound of s low-ftytng jet plane. And h is oe the threshold of pain for (he human cm. While (he 600-A-high emission stack, dart-connected to the induced-draft faa. wras initially found so be s primary none source. coovenbouaJ filtering of the o c k tuung from the top of the stack revolved this problem. It was then determined that a basic primary nosse source, which required acoustical treatmeat, was the induced-draft-faa caa- Tharmaf/aceuaticU ptnwh wvrt rutaUsd on ductwork leading from mducud-drafttan equip ment (l*ft) to No. 3 unit's 600ft high stack Additional pantfs cover ductwork las png to In duced-drift fan houtmg and ductwork from precipitator to tan (right) UiaiiMi t *t*m War IS. iCuvqu itfkViitu u r*HBat Parse LIA14970 kgs, tad (Kc ductwork Wading to tad from them. According to Frank J. Wells. of Uko'i elcctncal engineering staff, the ned enclosure* for the ductwork tad fan bousing provided a very Urge KHiod-radiaUfig surface, much like that of a gigantic loudspeaker lyitem. Therefore, Liloo decided to enclose both the fan bousing and the ductwork inaidc a sound-burner system. This sound barrier had to be able to with stand the approinnately OOF operating temperatures of the equipment. To help solve the problem, Liko called on Trtmoo Inc, ChWsto (HIT manufacturer of prefabricated thermal* insulation punch. While Traasco had installed in standard thermal insulation panda at more than 50 power pUn* throughout the country, the company had only recently developed two type* of insulated panda specifically designed to provide a loaeftnaiamwa toes of up to 52 db. Uko'i Northport pUot b the Ant application of the company's combination thermal/nconstKal pand system. Noise tnmsiiuia Visa capabilities of the new panel tystetn arc achieved through use of other a tingle or double layer of I/fi4-a.-thick sheet lead, weighing I fb/sq ft. For maximum eftocncy, the lead n sandwiched between laym of the mineral wool (hat h one of the standard maiefiab used so produce the company's thermal insulation pan da According so the Lead Industries Aam. shed lead was seWacd for the thermal/acoustical pand became rt * found lo be the moat cftocat sound- fisngrtl ncawafie peaks. iaadrty metsisd wth hand-ponced soOst tods, witam one or two l/fi4wvd*ch layers of Wad. Undwckd betuem layers d >nwara< wok banier material among the many tedad. Five matenals are used to produce the new thermal/acoustical panel: an exterior sheet of either corrugated or box-rib aluminum or galvanized steel; a layer of mineral-wool insulation; angle or double layers of sheet kad sand wiched between one or more additional layers of mineral wool; a layer of aluminum foil; and a wke-mesh re tainer on the sound-source side of the pand. The box-rib pands art available In 40-in. widths; comtgated panda m 52-40. widths. The thickness of the thermal maniatioe is established a* a function of the operating temperature of the equipment lo be enclosed.`T^e choice ofone or two layers of shoe * lead is determined by the amount of no n reduction desired. Transoo held engineers worked at the site with Liko lo install the panda *Wc learned from experience as we began instilling the system.* aeys Wdk. After enclosing Unit I and its associated duct work. he points out, n was Warned that panels containing one layer of sheet lead were not sufficient so solve the spe cific nooc-control problems associated with the equipment This was due to the fad that none levels ta the mdaceddraft-fan housing were much higher than ta (he ductwork Wading to and from the homing The location and specific geographi cal oncelaboa of the equipment, and the resultant travel path of the aoar generated by the equipment, can tometuna resolve the potential acme-annoyancc problem-but k caa also crease more problems. For caampk. * was learned that noise emanating from the east and west sides of the plant would have to be carefully controlled, since it travels directly ana without restriction toward the surrounding community. However, noise emanating from the north and south sides of the plant-as caused by Unit I1) Induced-draft-fan housing, foe instance--was not a par* ocular problem, because it either than pates over Long Island Sound or is blocked by high bluffs behind the plant Based on this knowledge, thermal bsulatioQ wuh two sheets of l-lb/sq ft lead was specified to enclose the indvced-drmft-faa housing of Unit 2-ori ented east and west as well as (he duct work ksdmg from the housing to the suck. Ductwork Wading from the parUculate-coJlector bouse to the tndoewddraft fan was covered in thermal bidstioo with only one sheet of lead. With tha problem solved, the bk of controlling the noise from Unit 5 began. While different than the Ant two units. . met aa electrostatic precipitator had been included tn its design, experience : gamed m controlling none from tbc Am two units indicated that a combina tion of all throe (vpes of panels (her mal only, thermal'/acoustic (one layer of Wad). and thermal/acoustic (two lay er* of lead}--should be used to endoae bs fan. ductwork, and precipitator. Fen. the ductwork leading from the power plant to (he preoprtetor and bs hoppers (used to remove particulate msnee resulting from operation of the precipitator) were enclosed with Aermal-maulsimp panels. Next, the preetpbasoe and ductwork leading from k to the induced-draft faa were endcsed in thermal/acoustical paneb coolammg one layer of sheet Wad. These, the in duced-draft-fan bousing and (he duct work Wading from H to (he stack were endewed with thermal/acoustical panels coeutaiag (wo layers of lead. Tn achieve maximum acoustical insulation, these two Wad sheets are separated by a layer of mineral wool. In essence, the Wad remains, "free-Aoating" and b therefore more effective. The ductwork and induced-draft-fan housing fur the first two units required about 20.000 sq ft of panels. Approxi mately. 53.000 sq ft were required to en close the third unit because, in addition to (he unit's induced-draft-fan' housing and associated ductwork, its precipitator bowing and the ductwork from (he pUni u> the prrapitator also had to be entitled. 7 ranwo delivered the panda 'precut to size and ready for installation. : Thb considerably reduced installation : costs and decreased equipment down time whtk the Ant two units were being modified Also, use of the prccut panels permitted the third unit to be readied for operational testing faster than would have been possible had the pands not been cut to sac. n - . ij ' -,i . a. . :* ill & fLr - V- g i if v "4 .i s -an 5ss* -w * } "`t i 5 ,2 1 A 26-pege brochure Including descriptions o( various leed bearing element* in sheet. laminated, powder, or bulk form for acoustical purposes end Including lists ct manufacturers. Bectncal World kU. IS, 1971 Distributed by Lead Industries Association, Inc. m kUtftoon Am Hmm Yfft. M.V. 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